COMPUTATIONAL STUDY OF FLOW AND HEAT TRANSFER WITH ANTI CROSS-FLOWS (ACF) JET IMPINGEMENT COOLING FOR DIFFERENT HEIGHTS OF CORRUGATE

摘要

In the present study, a flow visualization and heat transfer investigation is carried out computationally on a flat plate with 10x1 array of impinging jets from a corrugated plate. This corrugated structure is an Anti-Cross Flow (ACF) technique which is proved to nullify the negative effects of cross-flow thus enhancing the overall cooling performance. Governing equations are solved using k-ω Shear Stress Transport (SST) turbulence model in commercial code FLUENT. The parameter variation considered for the present study are (i) three different heights of ACF corrugate (C/D=1, 2 & 3) and (ii) two different jet-to-target plate spacing (H/D=1 & 2). The dependence of ACF structure performance on the corrugate height (C/D) and the flow structure has been discussed in detail, therefore choosing an optimum corrugate height and visualizing the three-dimensional flow phenomena are the main objectives of the present study. The three-dimensional flow separation and heat transfer characteristics are explained with the help of skin friction lines, upwash fountains, wall eddies, counter-rotating vortex pair (CRVP), and plots of Nusselt number. It is found that the heat transfer performance is high at larger corrugate heights for both the jet-to-plate spacing. Moreover, the deterioration of the skin friction pattern corresponding to the far downstream impingement zones is greatly reduced with ACF structure, retaining more uniform heat transfer pattern even at low H/D values where the crossflow effects are more dominant in case of the conventional cooling structure. In comparison of the overall heat transfer performance the difference between C/D=3 & C/D=2 for H/D=2 is significantly less, thus making the later as the optimal configuration in terms of reduced channel height.